Disk drive dimensions are normally limited by a form factor, an industry standard of length, width and height dimensions. This is a rigid standard that is often more the result of accident than design. The standard is usually the result of a progression of events starting with a flexible disk drive, that sets the standard or in accordance with which using systems provide space in their designs. Rigid disk drives have usually been adapted to replace a flexible disk drive in the same space and have therefore been required to meet the same dimensions in order to obtain acceptance from the users of such storage devices. Drives incorporating 31/2 inch disks have a form factor that is 5.75 inches long, 4 inches wide and 1.625 inches high.
Disk drives are continuously being redesigned to maximize areal density of data on each disk. In the present invention the disk drive design has been maximized for volumetric data density of the entire drive rather than just areal density of the data on each disk. The goal of volumetric density is to increase the number of disks and the number of electronic support features for the disk drive within the form factor for the disk drive assembly. Maximizing volumetric density includes not only packing more disks in the vertical form factor for the disk drive assembly, but also where to place the electrical components exterior of the enclosed head-disk assembly such as the data channel electronics that go with the disk pack, microprocessor, servo and motor drive electronics. As the number of disks and storage capacity increase, the data handling and manipulation tasks become more complex as the opportunities for electronic component mounting diminish. The first casualty as the disk stack height is increased is the large printed circuit card, coextensive with width and length that has commonly extended along the entire bottom surface.